EL NINO IN A COUPLED OCEAN—ATMOSPHERE GENERAL CIRCULATION MODEL

E. M. Volodin and N. A. Dianskii

The interannual variability of equatorial Pacific sea surface temperature (SST) is simulated in a 80-year experiment with the INM RAS coupled ocean—atmosphere general circulation model. The model correctly reproduces the observed spectral peak of variability at 3—5 years and observed features of negative SST anomalies in comparison with positive ones. However, the SST variability maximum in the El Nino region is shifted in the model to the west compared with the observational data. A possible cause is the overestimation of the mean velocity of upwelling in the central and western Pacific. The improved simulation of the El Nino statistics compared with the original version of the model is achieved by changing a parametrization of low cloud, deep convection, and dynamics in the atmospheric block and by using a C grid instead of a B grid in the ocean model.